For Mr. Verba, the decision to support Google’s plan was not easy or obvious. He has a unique perspective on the legal and intellectual debate because his various professional roles connect him to every aspect of the creation and use of books.

“It’s been dominating my life for the last year and a half,” said Mr. Verba, a prominent political scientist who has been a professor at Harvard for more than 30 years. Even now, he is cautious about the implications of the ambitious project.